wireguard-linux/arch/riscv, branch stable

RISC-V: KVM: Fix HSM hart status error propagation

2026-09-15T13:25:51Z

kvm_sbi_hsm_vcpu_get_status() returns SBI_ERR_INVALID_PARAM when the requested hart does not exist. However, the HART_STATUS case returns from the SBI handler without storing this error in retdata->err_val. As a result, a guest querying the status of a non-existent hart observes SBI_SUCCESS instead of SBI_ERR_INVALID_PARAM. Use the common SBI error handling path for HART_STATUS after saving a valid hart state in retdata->out_val. This preserves the returned error when kvm_sbi_hsm_vcpu_get_status() fails. Fixes: bae0dfd74e01 ("RISC-V: KVM: Modify SBI extension handler to return SBI error code") Cc: stable@vger.kernel.org Assisted-by: LLM Signed-off-by: Tan Chi Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20260914031146.446157-1-tanchi25@mails.ucas.ac.cn Signed-off-by: Anup Patel

RISC-V: KVM: Fix perf-backed counter accounting across stop and read

2026-09-15T13:25:51Z

pmu_ctr_read() adds the event count returned by perf_event_read_value() to counter_val, which can accumulate the same count repeatedly across reads. kvm_riscv_vcpu_pmu_ctr_stop() also leaves counter_val stale by not folding the current event count into it. Make reads of perf-backed counters side-effect free, and use perf_event_pause() when stopping a counter to fold the current event count into counter_val while resetting it. This preserves the counter value across stop/start and lets the snapshot path use counter_val directly. Fixes: 0cb74b65d2e5 ("RISC-V: KVM: Implement perf support without sampling") Signed-off-by: SeungJu Cheon Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20260825083719.643970-4-suunj1331@gmail.com Signed-off-by: Anup Patel

RISC-V: KVM: Report snapshot write failure to the guest

2026-09-15T13:25:51Z

If kvm_vcpu_write_guest() fails while updating the PMU snapshot area on counter stop, the guest may receive SBI_SUCCESS without the snapshot being updated, leaving stale data in shared memory. Return SBI_ERR_FAILURE when the snapshot write fails. Fixes: c2f41ddbcdd7 ("RISC-V: KVM: Implement SBI PMU Snapshot feature") Signed-off-by: SeungJu Cheon Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20260825083719.643970-3-suunj1331@gmail.com Signed-off-by: Anup Patel

RISC-V: KVM: Preserve firmware counter value across stop/start

2026-09-15T13:25:51Z

Firmware events accumulate in kvpmu->fw_event[].value while running, but counter stop only clears fw_event[].started without saving the value back to pmc->counter_val. A subsequent counter start without SBI_PMU_START_FLAG_SET_INIT_VALUE reloads the stale counter_val into fw_event[].value, losing all events counted so far. Save fw_event[].value into counter_val when actually stopping a running counter, and remove the now redundant synchronization from the snapshot path. Fixes: badc386869e2c ("RISC-V: KVM: Support firmware events") Signed-off-by: SeungJu Cheon Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20260825083719.643970-2-suunj1331@gmail.com Signed-off-by: Anup Patel

RISC-V: KVM: Fix sdata leak and stale snapshot_addr in snapshot_set_shmem

2026-09-15T13:25:51Z

A guest may call SBI_PMU_SNAPSHOT_SET_SHMEM repeatedly. Each call overwrites kvpmu->sdata without freeing the old buffer (memory leak), and if a later kvm_vcpu_write_guest() fails, the error path frees sdata but leaves snapshot_addr stale. A subsequent SBI_PMU_COUNTER_START then passes the INVALID_GPA check and crashes the host with a NULL buffer in kvm_vcpu_read_guest(). Fix this by clearing the previously installed snapshot area before installing a new one, which keeps sdata and snapshot_addr consistent. The SBI spec suggests a single invocation but defines no error code for repeated calls, so KVM must tolerate them. Fixes: c2f41ddbcdd756 ("RISC-V: KVM: Implement SBI PMU Snapshot feature") Cc: stable@vger.kernel.org Signed-off-by: Zongmin Zhou Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20260826064117.58029-1-min_halo@163.com Signed-off-by: Anup Patel

KVM: riscv: Fix NACL hfence entry update order

2026-09-15T13:25:51Z

The SBI v3.0 specification (section 15.1.2) requires a nested HFENCE entry to be populated as follows: 1) find an unused entry with Config.Pending == 0 2) update the Page_Number and Page_Count words 3) update the Config word with Config.Pending set __kvm_riscv_nacl_hfence() writes the Config word first, so the SBI implementation (or NACL hardware) can observe a pending entry with pnum/pcount values left over from the previous use of that entry, resulting in incorrect TLB flush ranges. Write pnum and pcount first and the Config word last. Since the consumer is an external agent on coherent shared memory, use WRITE_ONCE() to stop the compiler from reordering the stores and smp_wmb() to make the parameter words globally visible before the Pending bit is set. Fixes: d466c19cead5 ("RISC-V: KVM: Add common nested acceleration support") Signed-off-by: Zongmin Zhou Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20260826075009.68952-1-min_halo@163.com Signed-off-by: Anup Patel

RISC-V: KVM: Propagate interrupted G-stage faults

2026-09-15T13:25:51Z

__kvm_faultin_pfn() reports an interrupted host page fault with KVM_PFN_ERR_SIGPENDING. RISC-V currently handles it as a generic error PFN and returns -EFAULT. Return -EINTR for the signal-pending sentinel so callers can distinguish an interrupted fault from an invalid userspace mapping. Do not log the expected interruption as a vCPU exit error. Fixes: 9d05c1fee837 ("RISC-V: KVM: Implement stage2 page table programming") Cc: stable@vger.kernel.org Signed-off-by: Xie Bo Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20260810051544.3953925-3-xb@ultrarisc.com Signed-off-by: Anup Patel

RISC-V: KVM: Release unused page after MMU invalidation

2026-09-15T13:25:51Z

If an MMU invalidation races with a G-stage fault, the fault handler skips installing the page but leaves ret set to zero. As a result, kvm_release_faultin_page() treats the page as used and can unnecessarily mark it dirty. Track the invalidation retry separately and release the page as unused, while preserving the existing return value so that the vCPU retries the fault. Fixes: 2ed90cb0938a ("KVM: RISC-V: Retry fault if vma_lookup() results become invalid") Cc: stable@vger.kernel.org Signed-off-by: Xie Bo Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20260810051544.3953925-2-xb@ultrarisc.com Signed-off-by: Anup Patel

RISC-V: KVM: Serialize IMSIC attributes with vCPU migration

2026-09-15T13:25:51Z

KVM device ioctls are not serialized against KVM_RUN. As a result, kvm_riscv_aia_imsic_rw_attr() can snapshot the physical CPU and HGEI of an IMSIC VS-file before a concurrent vCPU migration releases it. The HGEI can then be allocated to another vCPU before imsic_vsfile_rw() uses the stale tuple. A GET or SET attribute may consequently access the new owner's interrupt file. Serialize the entire IMSIC attribute operation with the target vCPU mutex. This prevents the VS-file from being migrated and recycled until the attribute access completes. Acquire the mutex killably so that the device ioctl remains interruptible while waiting for KVM_RUN to finish. Fixes: db8b7e97d613 ("RISC-V: KVM: Add in-kernel virtualization of AIA IMSIC") Cc: stable@vger.kernel.org Signed-off-by: Xie Bo Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20260810-imsic-attr-race-v2-1-00ed95ad321e@ultrarisc.com Signed-off-by: Anup Patel

RISC-V: KVM: Fix the conversion between vsip and hvip

2026-09-15T13:25:51Z

Per AIA spec 1.0 Section 6.3.2, the interrupt numbers 13-63 shares same bit position between related VS shadow CSRs and hypervisor CSRs. So there's a shift only for SSI, STI and SEI interrupt. Currently the KVM always does a shift for all the interrupts (include LCOFI with number 13) when doing the conversion between vsip and hvip. Fix this by only doing shift the SSI, STI and SEI. Add wrappers for doing the conversion between vsip and hvip. Fixes: 16b0bde9a37c ("RISC-V: KVM: Add perf sampling support for guests") Signed-off-by: Yicong Yang Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20260804134018.85497-1-yang.yicong@picoheart.com Signed-off-by: Anup Patel